Clock



FIG. 1 is a front elevational view of a clock showing my new design;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a front elevational view of another embodiment of my new design of FIGS. 1-3;

FIG. 5 is a side elevational view thereof;

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a clock, as shown and described. 